摘要 |
A box-side lip length L, which is the axial distance between a pin-nose-end corresponding point P of the box component 1 and a load surface 18b of a lip-side internal thread ridge 50 closest to the pin-nose-end corresponding point P, is 300 or more times as long as an insertion surface interval ´, which is the axial interval between an insertion surface 19b of an internal thread ridge at a position two or more ridges backwards from the lip-side internal thread ridge 50 and an insertion surface 19a of an external thread ridge facing the insertion surface 19b when tightened, that is, L ‰¥ 300 × ´. |
申请人 |
JFE STEEL CORPORATION |
发明人 |
NAGAHAMA, TAKUYA;TAKAHASHI, KAZUNARI;CHIKATSUNE, HIROSHI;YOSHIKAWA, MASAKI;TAKANO, JUN;KAWAI, TAKAMASA;UETA, MASATERU |